Sensory stimulation evokes in the central nervous system a complex series of neural events. With appropriate averaging techniques some of these events can be recorded from the human scalp and are called the averaged Evoked Potential (EP). The goal of this research is to develop EP analysis for the evaluation of disorders involving sensory dysfunction, and to further understand the neural basis of human sensory experience. Our strategy is to conduct, whenever possible, parallel studies in man and animals. Experiments are being conducted in five related areas: (1) Neural origins of EPs in man. The objective is to clarify the structures and pathways within the human brain which generate various EP components; such knowledge is fundamental both to basic and clinical studies. (2) Neural origins of EPs in non-human primates. In these studies we seek first to determine an optimal primate species for use as an animal model in human EP studies. In this species we will then carry out studies which cannot be performed on man with the object of further clarifying the neural origins and characteristics of EPs. (3) Epilepsy studies. These experiments continue our investigation of EP correlates of epilepsy with the goal of determining EP alterations in different seizure types and assessing the effects of anticonvulsant medication. (4) Collection and quantification of normative data. Such data are necessary for proper interpretation of "abnormal" responses from patients. (5) EP correlates of performance in cognitive tasks. By relating EPs to performance in well-defined reaction time paradigms, we may be able to separate those portions of EPs which are related to decision-making processes and to the subsequent motor act.